code: def test_str_split(process_test_df):
      """Test wrapper for Pandas `str.split()` method."""
  
      expected = process_test_df.assign(
          text=process_test_df["text"].str.split("_")
      )
  
      result = process_test_df.process_text(
          column_name="text", string_function="split", pat="_"
      )
  
      assert_frame_equal(result, expected)
  
imports: import numpy
  import pandas
  import pytest
  from pandas.testing import assert_frame_equal
label_desc: Use image node_id 10 for calling a global function with example usage: test_str_split(process_test_df) without return types